Use of aminotriarylmethanes for marking hydrocarbons and novel aminotriarylmethanes

ABSTRACT

Use of aminotriarylmethanes of the formula ##STR1## where the ring A may be benzofused, and 
     R 1  and R 2  are each substituted or unsubstituted C 1  -C 13  -alkyl or substituted or unsubstituted phenyl, or R 1  and R 2  are together with the nitrogen atom joining them together a heterocyclic radical, or else R 1  is hydrogen, 
     R 3  and R 4  are substituted or unsubstituted C 1  -C 20  -alkyl or else R 3  is hydrogen, and 
     X 1  and X 2  are each substituted or unsubstituted C 1  -C 13  -alkyl or a radical of the formula NR 1  R 2 , or else one of X 1  and X 2  is hydrogen, 
     for marking hydrocarbons, hydrocarbons comprising the abovementioned aminotriarylmethanes, a method for detecting the aminotriarylmethanes in hydrocarbons, and novel aminotriarylmethanes.

This application is a 371 of PCT/EP94/01941 filed Jun. 15, 1994.

The present invention relates to the use of aminotriarylmethanes of theformula I ##STR2## where the ring A may be benzofused,

R¹ and R² are identical or different and each is independently of theother C₁ -C₁₃ -alkyl with or without interruption by from 1 to 3 oxygenatoms in ether function and with or without amino or hydroxylsubstitution, or substituted or unsubstituted phenyl, or R¹ and R² aretogether with the nitrogen atom joining them together a 5- or 6-memberedsaturated heterocyclic radical with or without a further heteroatom, orelse R¹ is hydrogen,

R³ and R⁴ are identical or different and each is independently of theother C₁ -C₂₀ -alkyl with or without interruption by from 1 to 4 oxygenatoms in ether function and with or without amino, hydroxyl or phenylsubstitution, or else R³ is hydrogen, and

X¹ and X² are identical or different and each is independently of theother C₁ -C₁₃ -alkyl with or without interruption by from 1 to 3 oxygenatoms in ether function and with or without amino or hydroxylsubstitution, or a radical of the formula NR¹ R², where R¹ and R² areeach as defined above, or else one of X¹ and X² is hydrogen,

for marking hydrocarbons, hydrocarbons comprising theaminotriarylmethanes of the formula I, a method for detecting theaminotriarylmethanes of the formula I in hydrocarbons, and novelaminotriarylmethanes.

U.S. Pat. No. 5,145,573 discloses the use of triarylmethane dyes ortriarylmethanecarbinols for marking mineral oils.

It is an object of the present invention to provide novel markers forhydrocarbons. The novel markers shall be readily obtainable and solublein hydrocarbons. They shall also be simple to detect; specifically, evenvery small amounts of marker shall be visibilizable through a strongcolor reaction.

We have found that this object is achieved by the above-definedaminotriarylmethanes of the formula I.

Any alkyl appearing in the abovementioned formula I may bestraight-chain or branched.

Any substituted alkyl appearing in the abovementioned formula Igenerally has 1 or 2 substituents.

Any substituted phenyl appearing in the abovementioned formula I mayhave as substituents for example C₁ -C₄ -alkyl or C₁ -C₄ -alkoxy. Thesubstituents generally number from 1 to 3.

R¹ and R² combined with the nitrogen atom joining them together into a5- or 6-membered saturated heterocyclic radical with one further heteroatom can be for example pyrrolidinyl, piperidinyl, morpholinyl,piperazinyl or N-(C₁ -C₄ -alkyl)piperazinyl.

R¹, R², R³, R⁴, X¹ and X² are each for example methyl, ethyl, propyl,isopropyl, butyl, isobutyl, sec-butyl, pentyl, isopentyl, neopentyl,tert-pentyl, hexyl, 2-methylpentyl, heptyl, octyl, 2-ethylhexyl,isooctyl, nonyl, isononyl, decyl, isodecyl, undecyl, dodecyl, tridecyl,3,5,5,7-tetramethylnonyl, isotridecyl (the above designations isooctyl,isononyl, isodecyl and isotridecyl are trivial names derived from theoxo process alcohols--cf. Ullmann's Encyklopadie der technischen Chemie,4th edition, Volume 7, pages 215 to 217, and Volume 11, pages 435 and436), 2-hydroxyethyl, 2- or 3-hydroxypropyl, 2- or 4-hydroxybutyl,5-hydroxypentyl, 6-hydroxyhexyl, 5-hydroxy-3-oxapentyl, 2-aminoethyl, 2-or 3-aminopropyl, 2- or 4-aminobutyl, 5-aminopentyl, 6-aminohexyl,7-aminoheptyl, 8-aminooctyl, 5-amino-3-oxapentyl, 6-amino-3-oxahexyl,6-amino-4-oxahexyl, 7-amino-4-oxaheptyl, 8-amino-3,6-dioxaoctyl,3-aminoprop-2-yl, 2-methoxyethyl, 2-ethoxyethyl, 2-propoxyethyl,2-isopropoxyethyl, 2-butoxyethyl, 2- or 3-methoxypropyl, 2- or3-ethoxypropyl, 2- or 3-propoxypropyl, 2- or 3-butoxypropyl, 2- or4-methoxybutyl, 2- or 4-ethoxybutyl, 2- or 4-propoxybutyl,3,6-dioxaheptyl, 3,6-dioxyoctyl, 4,8-dioxanonyl, 3,7-dioxaoctyl,3,7-dioxanonyl, 4,7-dioxaoctyl, 4,7-dioxanonyl, 2- or 4-butoxybutyl,4,8-dioxadecyl, 3,6,9-trioxadecyl or 3,6,9-trioxaundecyl.

R³ and R⁴ may each also be for example tetradecyl, pentadecyl,hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, benzyl, 1- or2-phenylethyl, 3,6,9-trioxadodecyl, 3,6,9,12-tetraoxatridecyl or3,6,9,12-tetraoxatetradecyl.

Preference for marking hydrocarbons is given to the use ofaminotriarylmethanes of the formula I where R¹ and R² are eachindependently of the other C₁ -C₄ -alkyl or substituted or unsubstitutedphenyl, or else R¹ is hydrogen.

Preference for marking hydrocarbons is further given to the use ofaminotriarylmethanes of the formula I where R³ and R⁴ are eachindependently of the other C₆ -C₁₃ -alkyl with or without interruptionby 1 or 2 oxygen atoms in ether function, or else R³ is hydrogen.

Preference for marking hydrocarbons is further given to the use ofaminotriarylmethanes of the formula I where X¹ and X² are eachindependently of the other C₁ -C₄ -alkyl or C₁ -C₄ -dialkylamino, orelse one of X¹ and X² is hydrogen.

The present invention further provides hydrocarbons comprising one ormore of the aminotriarylmethanes of the formula I.

Preference is given to hydrocarbons comprising one or more of theaminotriarylmethanes of the formula I where R¹ and R² are eachindependently of the other C₁ -C₄ -alkyl or substituted or unsubstitutedphenyl, or else R¹ is hydrogen.

Preference is further given to hydrocarbons comprising one or more ofthe aminotriarylmethanes of the formula I where R³ and R⁴ are eachindependently of the other C₆ -C₁₃ -alkyl with or without interruptionby 1 or 2 oxygen atoms in ether function, or else R³ is hydrogen.

Preference is further given to hydrocarbons comprising one or more ofthe aminotriarylmethanes of the formula I where X¹ and X² are eachindependently of the other C₁ -C₄ -alkyl or C₁ -C₄ -dialkylamino, orelse one of X¹ and X² is hydrogen.

Hydrocarbons for the purposes of the present invention are aliphatic oraromatic hydrocarbons which are liquid under standard conditions. Theyare in particular mineral oils, for example motor fuels, such asgasoline, kerosine or diesel fuel, or oils, such as heating oil orengine oil.

The aminotriarylmethanes of the formula I are especially suitable formarking mineral oils where some form of marking is mandatory, forexample for tax reasons. To keep the costs for this to a minimum, it isdesirable to keep the amount of marker used to a minimum.

To mark hydrocarbons, the aminotriarylmethanes of the formula I are usedeither without a solvent or in the form of solutions. Suitable solventsare organic solvents. Preference is given to using aromatichydrocarbons, such as toluene, xylene, dodecylbenzene,diisopropylnaphthalene or a mixture of higher aromatics available fromShell as Shellsol® AB. To avoid the resulting solutions having a highviscosity, the concentration of aminotriarylmethane I chosen for thesolution generally ranges from 20 to 80% by weight, based on thesolution.

The aminotriarylmethanes of the formula I to be used according to thepresent invention permit very simple detection of marked hydrocarbons,even if the marker is present only in a concentration of about 10 ppm orless.

The presence in hydrocarbons of the aminotriarylmethanes of the formulaI used as markers is advantageously detected by treating the mineral oilwith an aqueous alcoholic medium comprising a protic acid with orwithout halide of the metals zinc, aluminum or tin.

The addition of the protic acid, and optionally the metal halide, to themarked hydrocarbon results in a clearly visible color reaction throughthe formation of a triarylmethane dye, which transfers to the aqueousalcoholic phase.

Suitable alcohols include for example ethanol, propanol or1-methoxypropan-2-ol. The use of ethanol is preferred.

Suitable protic acids for the method of the present invention include inparticular so-called strong acids, ie. protic acids with a pKa≦3.5.Suitable such acids include for example inorganic or organic acids, suchas perchloric acid, hydroiodic acid, hydrochloric acid, hydrobromicacid, hydrofluoric acid, sulfuric acid, nitric acid, phosphoric acid,benzenesulfonic acid, naphthalenesulfonic acid, methanesulfonic acid,oxalic acid, maleic acid, chloroacetic acid, dichloroacetic acid andbromoacetic acid. In some cases it can be of advantage to buffer theseacids, for example by adding acetic acid.

Particular emphasis is given to inorganic acids, and hydrochloric acidor sulfuric acid is of particular importance.

Suitable halides of the metals zinc, aluminum or tin include for examplezinc chloride, zinc bromide, aluminum chloride, aluminum bromide and tintetrachloride.

Particular emphasis is given to zinc chloride.

It is generally sufficient to extract about 20 ml of the mineral oilmarked according to the present invention with 10 ml of an aqueousalcoholic solution of a protic acid, optionally in the presence of themetal halide, to obtain this color reaction. It is also possible to usean aqueous alcoholic solution of the metal halide alone, since itlikewise has an acidic reaction.

The concentration of protic acid in the aqueous alcoholic solution isgenerally from 5 to 50% by weight, preferably from 10 to 30% by weight.The concentration of metal halide is generally from 10 to 20% by weightand the concentration of alcohol is generally from 10 to 40% by weight.

Preference is given to a method for detecting aminotriarylmethanes ofthe formula I where R¹ and R² are each independently of the other C₁ -C₄-alkyl or substituted or unsubstituted phenyl, or else R¹ is hydrogen.

Preference is further given to a method for detectingaminotriarylmethanes of the formula I where R³ and R⁴ are eachindependently of the other C₆ -C₁₃ -alkyl with or without interruptionby 1 or 2 oxygen atoms in ether function, or else R³ is hydrogen.

Preference is further given to a method for detectingaminotriarylmethanes of the formula I where X¹ and X² are eachindependently of the other C₁ -C₄ -alkyl or C₁ -C₄ -dialkylamino, orelse one of X¹ and X² is hydrogen.

The present invention further provides aminotriarylmethanes of theformula Ia ##STR3## where the ring A may be benzofused,

R¹ and R² are identical or different and each is independently of theother C₁ -C₁₃ -alkyl with or without interruption by from 1 to 3 oxygenatoms in ether function and with or without amino or hydroxylsubstitution, or substituted or unsubstituted phenyl, or R¹ and R² aretogether with the nitrogen atom joining them together a 5- or 6-memberedsaturated heterocyclic radical with or without a further heteroatom, orelse R¹ is hydrogen,

Y¹ and Y² are identical or different and each is independently of theother C₁ -C₂₀ -alkyl with or without interruption by from 1 to 4 oxygenatoms in ether function and with or without amino, hydroxyl or phenylsubstitution, or else Y¹ is hydrogen, and

X¹ and X² are identical or different and each is independently of theother C₁ -C₁₃ -alkyl with or without interruption by from 1 to 3 oxygenatoms in ether function and with or without amino or hydroxylsubstitution, or a radical of the formula NR¹ R², where R¹ and R² areeach as defined above, or else one of X¹ and X² is hydrogen.

For exemplification of the individual radicals in the formula Ia,reference is made to the earlier observations.

Preference is given to aminotriarylmethanes of the formula Ia, where R¹and R² are each independently of the other C₁ -C₄ -alkyl or substitutedor unsubstituted phenyl, or else R¹ is hydrogen.

Preference is further given to aminotriarylmethanes of the formula Iawhere Y¹ and Y² are each independently of the other C₆ -C₁₃ -alkyl withor without interruption by 1 or 2 oxygen atoms in ether function, orelse Y¹ is hydrogen.

Preference is further given to aminotriarylmethanes of the formula Iawhere X¹ and X² are each independently of the other C₁ -C₄ -alkyl or C₁-C₄ -dialkylamino, or else one of X¹ and X² is hydrogen.

The novel aminotriarylmethanes of the formula Ia as well as the otheraminotriarylmethanes of the formula I known from EP-A-433 813 areobtainable in a conventional manner, for example as described inEP-A-433 813.

For example, a triarylmethane base of the formula II ##STR4## where R¹,R², X¹, X² and the ring A are each as defined above, can be reacted withan amine of the formula IIIa or IIIb ##STR5## where R³, R⁴, Y¹ and Y²are each as defined above.

The novel aminotriarylmethanes of the formula Ia are readily soluble inorganic solvents and, as mentioned earlier, are advantageously suitablefor marking hydrocarbons.

The Examples which follow illustrate the invention.

EXAMPLE 1

A) Preparation

14.2 g of ethylviolet base of the formula ##STR6## and 4 g of3-(2-ethylhexyloxy)propylamine were refluxed in 100 ml of toluene for 7h. After cooling down, the reaction mixture was washed with water anddried over sodium sulfate. Removal of the solvent left 16.9 g of acompound of the formula ##STR7## [λ_(max) (in acetic acid): 587 nm]whichstill contained about 10% of starting material as by-product.

The same method gives the aminotriarylmethanes of the formula ##STR8##listed in the table below:

    __________________________________________________________________________    Ex. No.                                                                           L.sup.1                                                                            L.sup.2                                                                            L.sup.3                                                                                           1 #STR9##                                                                              HD max  (in acetic acid)           __________________________________________________________________________                                               [nm]                               2         N(C.sub.2 H.sub.5).sub.2.2                                                        2 #STR10##            3-(2-Methoxy- ethoxy)propylamino                                                     587                                3        N(C.sub.2 H.sub.5).sub.2b.2                                                        2 #STR11##          2-Ethylhexylamino                                                                                          578            4        N(C.sub.2 H.sub.5).sub.2b.2                                                        3 #STR12##          3-(2-Methoxy- ethoxy)propylamino                                                         613                              5        N(C.sub.2 H.sub.3).sub.2b.2                                                        3 #STR13##          3-(2-Methoxy- ethoxy)propylamino                                                         591                              6        N(C.sub.2 H.sub.3).sub.2b.2                                                        2 #STR14##          3-(2-Methoxy- ethoxy)propylamino                                                         589                              7                                 N(C.sub.2 H.sub.5).sub.2                                  2 #STR15##          3-(2-Ethylhexyl- oxy)propylamino                                                         627                              8                                 N(C.sub.2 H.sub.5).sub.2                                  2 #STR16##          3-(2-Methoxy- ethoxy)propylamino                                                         627                              9                                 N(C.sub.2 H.sub.5).sub.2                                  2 #STR17##          3-(4-Hydroxy- butoxy)propylamino                                                         627                              10     H                          N(C.sub.2 H.sub.5).sub.2                                  2 #STR18##          Isopentylamino                                                                                                626         11     H                          N(C.sub.2 H.sub.5).sub.2                                  2 #STR19##          10-Amino-4,7- dioxadecylamino                                                               627                           12     H                          N(C.sub.2 H.sub.5).sub.2                                  2 #STR20##          Bis(2-ethylhexyl)- amino                                                                         626                      __________________________________________________________________________

B) Application

General Method

Commercial diesel fuel is admixed with a 40% strength by weight solutionof the marker in a commercial mixture of higher aromatics--Shellsol® AB(from Shell).

The amount of marker added is 10 ppm.

20 ml of marked diesel fuel are vigorously shaken up with 20 ml of thereagent solution (10% strength by weight zinc chloride solution in 60:40v/v water/ethanol, pH adjusted to 2 by addition of 85% strength byweight acetic acid). The lower, aqueous phase takes on a distinct color.The aqueous phase can be measured photometrically against a solution ofknown concentration.

The above-listed markers (Examples 1 to 12) each gave similar results.

We claim:
 1. A method of marking hydrocarbons comprising adding to ahydrocarbon a marking substance which is an aminotriarylmethane of theformula I ##STR21## where the ring A may be benzofused, R¹ and R² areidentical or different and each is independently of the other C₁ -C₁₃-alkyl with or without interruption by from 1 to 3 oxygen atoms in etherfunction and with or without amino or hydroxyl substitution, orsubstituted or unsubstituted phenyl, or R¹ and R² are together with thenitrogen atom joining them together a 5- or 6-membered saturatedheterocyclic radical with or without a further heteroatom, or else R¹ ishydrogen,R³ and R⁴ are identical or different and each is independentlyof the other C₁ -C₂₀ -alkyl with or without interruption by from 1 to 4oxygen atoms in ether function with or without phenyl substitution, andwith amino or hydroxyl substitution or else R³ is hydrogen and X¹ and X²are identical or different and each is independently of the other C₁-C₁₃ -alkyl with or without interruption by from 1 to 3 oxygen atoms inether function and with or without amino or hydroxyl substitution, or aradical of the formula NR¹ R², where R¹ and R² are each as definedabove, or else one of X¹ and X² is hydrogen.
 2. The method of claim 1,wherefor R¹ and R² are each independently of the other C₁ -C₄ -alkyl orsubstituted or unsubstituted phenyl, or else R¹ is hydrogen.
 3. Themethod of claim 1, wherefor R³ and R⁴ are each independently of theother C₆ -C₁₃ -alkyl with or without interruption by 1 or 2 oxygen atomsin ether function, with amino or hydroxyl substitution or else R³ ishydrogen.
 4. The method of claim 1, wherefor X¹ and X² are eachindependently of the other C₁ -C₄ -alkyl or C₁ -C₄ -dialkylamino, orelse one of X¹ and X² is hydrogen.
 5. A composition comprising ahydrocarbon and one or more aminotriarylmethanes of the formula I as setforth in claim
 1. 6. A method for detecting the presence ofaminotriarylmethanes of the formula I ##STR22## where the ring A may bebenzofused,R¹ and R² are identical or different and each is independentof the other C₁ -C₁₃ -alkyl with or without interruption by from 1 to 3oxygen atoms in ether function and with or without amino or hydroxylsubstitution, or substituted or unsubstituted phenyl, or R¹ and R² aretogether with the nitrogen atom joining them together a 5- or 6-memberedsaturated heterocyclic radical with or without a further heteroatom, orelse R¹ is hydrogen, R³ and R⁴ are identical or different and each isindependently of the other C₁ -C₂₀ -alkyl with or without interruptionby from 1 to 4 oxygen atoms in ether function, with or without phenylsubstitution, and with amino or hydroxyl substitution, or else R³ ishydrogen, and X¹ and X² are identical or different and each isindependently of the other C₁ -C₁₃ -alkyl with or without interruptionby from 1 to 3 oxygen atoms in ether function and with or without aminoor hydroxyl substitution, or a radical of the formula NR¹ R², where R¹and R² are each as defined above, or else one of X¹ and X² ishydrogen,in hydrocarbons, which comprises treating the hydrocarbon withan aqueous alcoholic medium comprising a protic acid with or without ahalide of the metals zinc, aluminum or tin.
 7. Aminotriarylmethane ofthe formula Ia ##STR23## where the ring A may be benzofused,R¹ and R²are identical or different and each is independently of the other C₁-C₁₃ -alkyl with or without interruption by from 1 to 3 oxygen atoms inether function and with or without amino or hydroxyl substitution, orsubstituted or unsubstituted phenyl, or R¹ and R² are together with thenitrogen atom joining them together a 5- or 6-membered saturatedheterocyclic radical with or without a further heteroatom, or else R¹ ishydrogen, Y¹ and Y² are identical or different and each is independentlyof the other C₁ -C₂₀ -alkyl with or without interruption by from 1 to 4oxygen atoms in ether function, with or without phenyl substitution, andwith amino or hydroxyl substitution, or else Y¹ is hydrogen, and X¹ andX² are identical or different and each is independently of the other C₁-C₁₃ -alkyl with or without interruption by from 1 to 3 oxygen atoms inether function and with or without amino or hydroxyl substitution, or aradical of the formula NR¹ R², wherein R¹ and R² are each as definedabove, or else one of X¹ and X² is hydrogen.
 8. A method of markinghydrocarbons comprising adding to a hydrocarbon a marking substancewhich is an aminotriarylmethane of the formula I ##STR24## where thering A may be benzofused, R¹ and R² are identical or different and eachis independently of the other C₁ -C₁₃ -alkyl with or withoutinterruption by from 1 to 3 oxygen atoms in ether function and with orwithout amino or hydroxyl substitution, or substituted or unsubstitutedphenyl, or R¹ and R² are together with the nitrogen atom joining themtogether a 5- or 6-membered saturated heterocyclic radical with orwithout a further heteroatom, or else R¹ is hydrogen,X¹ and X² areidentical or different and each is independently of the other C₁ -C₁₃-alkyl with or without interruption by from 1 to 3 oxygen atoms in etherfunction and with or without amino or hydroxyl substitution, or aradical of the formula NR¹ R², where R¹ and R² are each as definedabove, or else one of X¹ and X² is hydrogen, and --N(R³)(R⁴) is selectedfrom the group consisting of --NH--C₃ H₆ OCH₂ CH(C₂ H₅)C₄ H₉ -- andNH--C₃ H₆ OC₂ H₄ OCH₃ --.
 9. A method of marking hydrocarbons comprisingadding to a hydrocarbon a marking substance which is anaminotriarylmethane of the formula I ##STR25## where the ring A isbenzofused, R¹ and R² are identical or different and each isindependently of the other C₁ -C₁₃ -alkyl with or without interruptionby from 1 to 3 oxygen atoms in ether function and with or without aminoor hydroxyl substitution, or substituted or unsubstituted phenyl, or R¹and R² are together with the nitrogen atom joining them together a 5- or6-membered saturated heterocyclic radical with or without a furtherheteroatom, or else R¹ is hydrogen,R³ and R⁴ are identical or differentand each is independently of the other C₁ -C₂₀ -alkyl with or withoutinterruption by from 1 to 4 oxygen atoms in ether function, and with orwithout amino, hydroxyl or phenyl substitution, or else R³ is hydrogen,and X¹ and X² are identical or different and each is independently ofthe other C₁ -C₁₃ -alkyl with or without interruption by from 1 to 3oxygen atoms in ether function and with or without amino or hydroxylsubstitution, or a radical of the formula NR¹ R², where R¹ and R² areeach as defined above, or else one of X¹ and X² is hydrogen.
 10. Amethod for detecting the presence of aminotriarylmethanes of the formulaI ##STR26## where the ring A may be benzofused,R¹ and R² are identicalor different and each is independent of the other C₁ -₁₃ -alkyl with orwithout interruption by from 1 to 3 oxygen atoms in ether function andwith or without amino or hydroxyl substitution, or substituted orunsubstituted phenyl, or R¹ and R² are together with the nitrogen atomjoining them together a 5- or 6-membered saturated heterocyclic radicalwith or without a further heteroatom, or else R¹ is hydrogen, X¹ and X²are identical or different and each is independently of the other C₁-C₁₃ -alkyl with or without interruption by from 1 to 3 oxygen atoms inether function and with or without amino or hydroxyl substitution, or aradical of the formula NR¹ R², where R¹ and R² are each as definedabove, or else one of X¹ and X² is hydrogen, and --N(R³)(R⁴) is selectedfrom the group consisting of --NH--C₃ H₆ OCH₂ CH(C₂ H₅)C₄ H₉ -- andNH--C₃ H₆ OC₂ H₄ OCH₃ --,in hydrocarbons, which comprises treating thehydrocarbon with an aqueous alcoholic medium comprising a protic acidwith or without a halide of the metals zinc, aluminum or tin.
 11. Amethod for detecting the presence of aminotriarylmethanes of the formulaI ##STR27## where the ring A is benzofused,R¹ and R² are identical ordifferent and each is independently of the other C₁ -₃ -alkyl with orwithout interruption by from 1 to 3 oxygen atoms in ether function andwith or without amino or hydroxyl substitution, or substituted orunsubstituted phenyl, or R¹ and R² are together with the nitrogen atomjoining them together a 5- or 6-membered saturated heterocyclic radicalwith or without a further heteroatom, or else R¹ is hydrogen, R³ and R⁴are identical or different and each is independently of the other C₁-C₂₀ -alkyl with or without interruption by from 1 to 4 oxygen atoms inether function, and with or without amino, hydroxyl or phenylsubstitution, or else R³ is hydrogen, and X' and X² are identical ordifferent and each is independently of the other C₁ -C₁₃ -alkyl with orwithout interruption by from 1 to 3 oxygen atoms in ether function andwith or without amino or hydroxyl substitution, or a radical of theformula NR¹ R², where R¹ and R² are each as defined above, or else oneof X¹ and X² is hydrogen,in hydrocarbons, which comprises treating thehydrocarbon with an aqueous alcoholic medium comprising a protic acidwith or without a halide of the metals zinc, aluminum or tin. 12.Aminotriarylmethane of the formula Ia ##STR28## where the ring A may bebenzofused, R¹ and R² are identical or different and each isindependently of the other C₁ -₃ -alkyl with or without interruption byfrom 1 to 3 oxygen atoms in ether function and with or without amino orhydroxyl substitution, or substituted or unsubstituted phenyl, or R¹ andR² are together with the nitrogen atom joining them together a 5- or6-membered saturated heterocyclic radical with or without a furtherheteroatom, or else R¹ is hydrogen,X¹ and X² are identical or differentand each is independently of the other C₁ -C₁₃ -alkyl with or withoutinterruption by from 1 to 3 oxygen atoms in ether function and with orwithout amino or hydroxyl substitution, or a radical of the formula NR¹R², where R¹ and R² are each as defined above, or else one of X¹ and X²is hydrogen, and --N(Y¹)(Y²) is selected from the group consisting of--NH--C₃ H₆ OCH₂ CH(C₂ H₅)C₄ H₉ -- and NH--C₃ H₆ OC₂ H4OCH₃ --. 13.Aminotriarylmethane of the formula Ia ##STR29## where the ring A isbenzofused, R¹ and R² are identical or different and each isindependently of the other C₁ -C₁₃ -alkyl with or without interruptionby from 1 to 3 oxygen atoms in ether function and with or without aminoor hydroxyl substitution, or substituted or unsubstituted phenyl, or R¹and R² are together with the nitrogen atom joining them together a 5- or6-membered saturated heterocyclic radical with or without a furtherheteroatom, or else R¹ is hydrogen,Y¹ and Y² are identical or differentand each is independently of the other C_(1-C) ₂₀ -alkyl with or withoutinterruption by from 1 to 4 oxygen atoms in ether function, and with orwithout amino, hydroxyl or phenyl substitution, or else Y¹ is hydrogen,and X¹ and X² are identical or different and each is independently ofthe other C₁ -C₁₃ -alkyl with or without interruption by from 1 to 3oxygen atoms in ether function and with or without amino or hydroxylsubstitution, or a radical of the formula NR¹ R², where R¹ and R² areeach as defined above, or else one of X¹ and X² is hydrogen.